Renewable Natural Gas (RNG) can be produced from carbonaceous and renewable feedstocks through a number of technologies including anaerobic digestion, landfill waste decomposition, gasification and pyrolysis. However, RNG contains a wide range of CO2 depending on the source, production method, has to be upgraded by removing most of the CO2 in order to meet the existing fuel specification of the Natural Gas Vehicle (NGV).
Further, NGVs typically operate with stoichiometric air-to-fuel ratio control with a three way catalyst (TWC) to control the emissions of NOx. One method for reducing NOx emissions further is with exhaust gas recirculation (EGR). EGR is the process of recirculating some of the exhaust with fresh air and fuel to minimize the nitrogen forming species. RNG has high levels of CO2 which could provide the same NOx emissions reduction benefit of EGR, but without the EGR technology. This has two benefits, 1) the EGR system is not needed thus reducing engine costs and 2) complete separation is not needed, thus reduction the RNG production costs.
Therefore, a need exists for equipment and methods to ease the transition from conventional fossil based fuels to the widespread adoption of renewable nature gaseous (NGR) fuels, while reducing or eliminating the need for EGR technology. The present invention satisfies those needs, as well as others, and overcomes the deficiencies of previously developed vehicle and natural gas energy solutions.